Change the light fixture's bulbs to the kind you want to use in your new fixture because new LED bulbs will make the tile colors look quite different. Then pick out some new wallpaper with maroon and gray in it. If you get some paint color chips, circle the ones that match the gray and maroon tiles, take them with you to the wallpaper store.

You can paint the wall a light shade of the gray and change the blinds to white. Paint the vanity white, black or stain it darker.

Others have had to deal with this exact tile combo: https://www.houzz.com/discussions/vintage-maroon-gray-tile-bathroom-decisions-dsvw-vd~905395

Hello - kudos for keeping your home original and making such progress! I think I’d want to tone the colors down a bit. I would paint the walls white, white shade, paint vanity, get a new light fixture & chrome fixtures. I think a new white shade would lighten things up tons. Good luck!